Log Message:
Update to soprano 2.9.4

2.9.4
    * Automatically delete fault transaction logs
    * Virtuoso backend supports parameterized queries which seem to
      consume less memory when inserting large amounts of plain text
2.9.3
    * Fix bugs in FilterModel
    * Optimize literal to N3 conversion
    * Virtuoso Backend - Optimize by around 5x
    * Fix potential memory leak in ErrorCache
2.9.2
    * Fix a crash in ServerCore on shutdown
    * Do no require X11 - not needed for compilation
    * Generate tag file for API docs
2.9.1
    * Faster streaming for datetime literals
    * Add a stop method in the LocalServer
    * Fix bugs in LocalSocket and AsyncQuery